Adjustable-window grating interferometer based on a Mach-Zehnder configuration for phase profile measurements of transparent samples

Abstract

This communication describes some details of polarization modulation that are useful in phase-shifting interferometry when applied to phase profile measurements of phase objects. Since non-destructive optical techniques allow surface measurement with high accuracy, a Mach-Zehnder configuration coupled to a 4-f arrangement using phase gratings placed on the Fourier plane was implemented to analyze phase objects. Each beam of the interferometer goes through a birefringent wave plate in order to achieve nearly circular polarization of opposite rotations, with respect to each other. The interference of the fields associated with replicated beams, centered on each diffraction order, is achieved varying the spacing of windows with respect to the grating period. Experimental results are presented for cases of four and nine simultaneously captured interferograms. Experimental SetupThe optical system proposed is shown in Fig. 1. It consists of a combination of a quarter-wave plate Q and a linear polarizing filter P 0 that generates linearly polarized light oriented

4D phase profile measurements using a single-shot phase shifting technique

“…This setup generates two displaced beams by moving a same distance Δx to mirror M and the polarizing Beam Splitter (PBS), enabling one to change the spacing x 0 between beams centres. He presented system simplifies other arrangements 1,4 . In order to generate cross circular polarization beams, we place a quarter wave plate (Q) on each beam, Q L and Q R placed in the path of beam A and B respectively.…”

“…Images are presented in 4D, these results show that dynamic phase objects can be analyzed with the proposed optical system used1,8 .…”